1. Technical Field
This invention relates to a printing apparatus, a printing material cartridge used for the printing apparatus, an adaptor for a printing material container, and circuit boards for these components.
2. Related Art
In recent years, a cartridge equipped with a memory device that stores information pertaining to printing materials (such as the amount of remaining ink) is used as a printing material cartridge. Also, a technology to detect attachment conditions of the printing material cartridges has been used. For example, in JP-A-2009-274438, attachment conditions of cartridges are detected by sending signals different from those for detecting the amount of remaining ink to the remaining ink sensor installed in the ink cartridge. In conventional technologies, attachment conditions have been commonly detected by the use of one or two of many terminals on the cartridge.
However, even if the proper attachment of the cartridge is detected, some other terminals not used for the detection of attachment conditions may sometimes be in poor contact with the terminals of the printing apparatus. Especially when the terminals for a memory device are in poor contact, a problem arises that errors tend to occur when data are written and read to and from the memory device.
Meanwhile, known technologies for detecting attachment conditions of ink cartridges include those described in JP-A-2002-198627 and JP-A-2009-241591. According to these documents, the attachment detection terminal on the cartridge side is grounded, while the attachment detection terminal on the printing apparatus side is pulled up to a power supply voltage via a resistance. If the attachment detection terminal on the cartridge side is in good contact with that on the printing apparatus side, the terminal on the printing apparatus side bears a ground voltage, whereas it is applied with a power supply voltage in case of non-contact. Therefore, attachment of the cartridge can be detected by monitoring the voltage of the attachment detection terminal on the printing apparatus side. Detection of cartridge attachment is also possible in a way opposite to that mentioned above, that is, by connecting the attachment detection terminal on the cartridge side to the power supply voltage, and at the same time, pulling down the attachment detection terminal on the printing apparatus side via a resistance. In general, cartridge attachment can be detected by connecting the attachment detection terminal on the cartridge side to a first fixed voltage, and connecting the attachment detection terminal on the printing apparatus side to a second fixed voltage via a resistance. However, keeping the voltage of the attachment detection terminal on the cartridge side constant may cause another problem. For example, in a configuration where the attachment detection terminal on the cartridge side is grounded, if the attachment detection terminal on the printing apparatus side bears a ground voltage from any cause, the system may erroneously identify a non-attached cartridge as attached. This would cause a problem of less reliability of attachment detection. Also, in a configuration where the attachment detection terminal on the cartridge side is grounded, if a high voltage (e.g. voltage for operating a print head) is mistakenly applied to the attachment detection terminal, a problem may arise that a large current flows through the attachment detection terminal to inflict damages to the circuitry of the cartridge or the printing apparatus.
In addition, on a circuit board installed on a cartridge, increased number of terminals or contact portions means a higher risk of poor contact at one or more of them. Therefore, there has been a desire to reduce the number of terminals and contact portions as much as possible.
The various problems mentioned above are not limited to ink cartridges but also applicable to printing material cartridges containing other types of printing materials (e.g. toner). Moreover, the same problem existed with liquid injection devices that inject different types of liquid other than the above printing materials and liquid containers (liquid storages) thereof. In addition, there have been similar problems with the detection of connection conditions between the circuit board terminals used for printing cartridges or liquid containers and the corresponding terminals on the apparatus side.
An object of the present invention is to provide a technology that properly checks attachment conditions of cartridges or their circuit boards. A second object of this invention is to provide a technology to properly evaluate whether the contact between terminals of a memory device for the cartridge or those of the circuit board and the corresponding apparatus-side terminals is enough or not. A third object of this invention is to provide a technology to perform attachment detection without keeping the attachment detection terminals of a cartridge or a circuit board for a cartridge at a fixed voltage. This invention does not need to have a configuration that achieves all of the above objects, and may be implemented in a way in which to have a configuration that achieves one of the above objects or other effects described later.